IF YOU would rather keep your desires to yourself, don’t volunteer to help Mario Beauregard with his research. Working at the University of Montreal in Quebec, Beauregard has been using a brain imaging machine to probe what is going on in the minds of people as they watch erotic videos. When they see images they find sexually desirable, the “higher” brain areas that deal with reasoning and logic go pretty quiet, but the basic emotion circuits show an unashamed burst of activity. It is almost the identical reaction you find in drug addicts when they get a craving. Beauregard will even know if you are concealing your arousal.
So, are you aroused by women or men or both? Are you trying to hide an addiction? Do you have a secret sexual fantasy? Or, taking it a step further, how would your brain react if the next picture were of a child? If you find these lines of questioning rather uncomfortable, you will see why some people are becoming exercised about exactly what brain scans can reveal and how they might one day be used. The motives of researchers like Beauregard may be honourable – he is trying to discover how normal, healthy desire can turn into addiction – but their work has raised some tough questions about privacy of thought and the ethics of probing the mind.
Brain imaging has already delved into our personal lives. Among other things, it has been used to investigate love, personality traits, political leanings, racial prejudice, tendency to violence, deception and moral reasoning. Scans can reveal early signs of brain disease and risk factors for mental illness. Studies are even beginning to encroach on legal issues such as whether we are responsible for our actions, whether it is possible to predict who is likely to commit a crime, and whether people are lying or have false memories.
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As pressure increases to bring brain scanning into the courts, the workplace and other walks of life, ethical dilemmas will inevitably arise. What will it mean to be able to peer into a person’s most private thoughts, or even their future? Could such research be misused, misinterpreted or used maliciously? No wonder neuroscientists, ethicists and lawmakers are starting to think long and hard about the implications.
From the start, brain imaging has been incredibly useful for looking at brain structure: tumours, stroke damage and degenerating tissue, for example, show up in scans as clearly as broken bones on an X-ray. More recently it has begun to produce a dynamic view of the brain, using blood flow as a way of inferring how hard different clusters of brain cells are working. To begin with, these fMRI and PET scanning studies tended to focus on basic brain processes such as planning movements, dealing with sensory signals, speaking or learning. But more and more researchers are turning their attention away from general findings and looking instead at personal brain processes – the sorts of things that define us as individuals. So, where earlier studies revealed that when we look at faces the signals are handled by a specialised face-recognition area, newer work may look at my brain’s response to a particular face and see how it differs from yours.
This approach grabbed the headlines a few years ago with a series of studies purporting to reveal hidden racial prejudices. First came the finding in 2000 by Elizabeth Phelps and her colleagues at New York University that the amygdala, a region associated with fear and other emotions, responded more strongly when white people viewed black faces than when they saw white faces. A year later, Alexandra Golby and colleagues from Stanford University in California found that the specialised face-recognition area, called the fusiform face area, responds more strongly to own-race faces. And at the end of last year, Jennifer Richeson and colleagues from Dartmouth College in New Hampshire found that when people interacted with a researcher or saw pictures of a person of a different race to their own, they subsequently performed worse at other tasks, and their brain activity suggested it was because they were expending effort on suppressing their race bias. On the back of these studies some commentators suggested that brain imaging was all set for use as a racism detector. A similar controversy followed a study by Marco Iacoboni at the University of California in Los Angeles. He imaged people with different political leanings as they viewed campaign videos, which led to suggestions that one day hidden scanners might reveal our voting intentions.
The ethical questions continue to pile up as other studies give insights into all kinds of areas that you might consider private. Josh Greene at Princeton University can tell how easily people make a difficult moral decision, such as whether they could cause a person’s death to save others. Tania Singer of University College London recently showed that brain activity could be correlated with how much people empathised with the pain and suffering of others. Then there are the studies revealing people’s levels of self-esteem by measuring activity in the frontal lobe, and fear by looking at responses in the amygdala.
But do these studies really tell us anything new about people? Researchers admit that brain imaging is pretty limited when it comes to making judgements and predictions about individuals. Iacoboni is first to acknowledge that there is little scope to turn his studies into a test for personal political allegiances. “We can’t put a subject in the scanner and tell if they are Republican or Democrat,” he says. “We may never get to that level.” And Phelps says she learned a lot about how the brain works, but not much about people’s racial attitudes. The scans did not reveal anything that had not already shown up in behavioural tasks. Indeed these tasks are routinely used to work out what the images from brain scans actually mean.
In an attempt to assess just how much can be inferred about an individual using brain scanning, Martha Farah from the University of Pennsylvania in Philadelphia reviewed studies of personality traits. The biggest ones to date have looked at neuroticism and extroversion, with some smaller studies on pessimism and persistence. Researchers have been fascinated to find that something as individual as personality can be reflected in definable differences in brain activity at all. Turhan Canli, a neuroscientist and psychologist from the State University of New York, Stony Brook, who conducted some of the work, is hopeful that this approach might eventually tell us the basis of personality differences, and lead to better understanding of mental health problems and to personalised treatments. But whether it would be useful in everyday situations, such as telling an employer that you are well suited to a particular job, is a different matter. Farah doubts it would. She believes that a brain scan is no more predictive than traditional interview methods. “It’s easier to get that information with a paper-and-pencil questionnaire,” she says.
But pictures from a brain scan somehow seem more real to people, Phelps says. That is partly because they convey deceptively simple messages, without any hint of all the variation, caveats, subtractions of baseline or “control” activity, and statistical processing that went before. As a result, claims to have pinpointed the “God spot”, the source of intelligence, or the location of our loving feelings, are far too simplistic. Canli worries that the images are so visually appealing that they will be misinterpreted. “There is nothing absolute in our data,” he says. Other researchers point out that their findings rest on interpretations from indirect measures of brain activity. So the idea that brain scans don’t lie simply doesn’t stand up. They do not reveal a more direct and honest view of what someone is thinking.
Bad behaviour
The fact that brain imaging technology currently falls short of mind reading hardly seems to matter, though. “Ready or not, these measures will have an increasing role in our lives,” Farah says. What counts is not how much scientists think can be inferred from their work, but how good it is perceived to be in the public domain. “Even if it turns out not to work,” says Hank Greely, professor of law at Stanford University, “a lot of damage could be done by people using it, believing that it works.” In almost every area of human life, we are interested in what people think – whether it be the realm of medical insurance, employment, the law, parenting or security services, he says. We may instinctively view our own thoughts as private property but that probably is not going to be enough to confine brain scanning to the labs. “A fear of terrorism goes a long way to making people ignore invasions of privacy,” Greely points out.
While people who take part in brain imaging studies are carefully protected, with ethics committees ensuring their anonymity and restricting the use of findings, there is no such protection for the rest of us. Judy Illes, a neuroscientist at Stanford University and a leader of the neuro-ethics debate, is particularly worried about coercion. “Imagine in an insurance context, where they order mapping studies to predict a propensity to violence, spontaneity, aggressive behaviour or conscientiousness in 16-year-old drivers,” she says. Likewise, there is nothing to protect us from medical insurance companies that could decline cover without a test, or employers using it to screen potential employees. At the moment it simply would not be worth their money, but that might not always be the case.
Another issue with serious ethical implications is the idea that scanning might be used to try to make predictions about future behaviour or illness: who might be a paedophile, who might be violent, who might develop a mental illness or prion disease, who could commit a crime. Would pressure be put on parents to give their children drugs to alter an “undesirable” personality trait or a low IQ? Take the study by Adrian Raine of the University of Southern California, who suggested that sociopathic murderers had reduced activity in some prefrontal and emotion centres. There has already been debate in the UK about detaining someone who might be a danger to society before they commit a crime, which underlines the dangers of the message becoming oversimplified.
A brainwave lie detector has already made its way into a US courtroom (see “Interrogating the grey matter”). This has highlighted concerns that in the US, individual judges can choose to admit any type of scientific evidence, relying only on testimony from expert witnesses appointed by the prosecution and defence and a set of principles laid down to help them. “As long as a judge is convinced that something is basically scientifically reliable, she can let it in,” says Greely. He thinks the decision to use brain imaging in court should be taken by a higher authority, and fears that once it is allowed by individual judges it will be here to stay. In the UK there are no set rules about how new scientific evidence comes to be accepted by the courts, but broad approval by peer review in the scientific literature is usually important, and expert witnesses must be approved by the Home Office.
It is reassuring at least to know that committees that influence lawmakers in both the US and the European Union are discussing the possible impact of brain scanning on our lives. In many ways the issues are similar to those of genetic testing, rehearsed over the past couple of decades as the human genome project came into being. This debate is perhaps even more fundamental, though. “Our brain function is all of us,” says Illes. “That includes our memory, our experiences, our whole belief system.” But given the complexity of what is going on in our minds and the variability from person to person in what shows up in scans, the idea of linking a particular pattern of activation with a given behaviour, especially something we might do in the future, is even more absurd than the notion of a gene for good parenting or intelligence. There is a common misconception that if something has a biological basis, it is also predictive or deterministic, says Canli. “It is not. Everything we know about the brain shows it is flexible. It continues to change.”
Interrogating the grey matter
In 2001, Terry Harrington’s brainwaves were presented as evidence in Pottawattamie county court in the backwoods of Iowa. He had been sentenced 23 years earlier to life imprisonment for a murder he claims he did not commit. The brainwave evidence was an attempt to win the right to appeal by proving that Harrington’s brain showed no glimmer of recognition for the crime scene, but telltale familiarity with the situation that was his alibi. Harrington’s claim failed, but the brainwave method was deemed acceptable.
The method, called brain fingerprinting, was developed by entrepreneurial scientist Lawrence Farwell and uses a network of scalp electrodes to pick up brainwave signals that have long been known to be associated with novelty (żěè¶ĚĘÓƵ, 9 June 2001, p 24). Farwell claims the technique could spot terrorists too, because their brainwaves would give away signs of familiarity with terrorist activities. But imagine someone working for a security service or as a professor of terrorism. Their brain would do the same. And there’s the rub. Familiarity with incriminating evidence is not necessarily an indication of guilt, nor is lack of recognition a sign of innocence.
Could functional brain imaging techniques do any better? On the surface the technology looks promising. Daniel Langleben of the University of Pennsylvania in Philadelphia has used fMRI to show that when people are lying there is greater activity in a region called the right anterior cingulate cortex. Giorgio Ganis and Stephen Kosslyn of Harvard University found that different types of lies produced different patterns of neural activity, depending on whether or not a story was coherent or well-rehearsed. All the lies, however, were associated with increased activation in many different brain areas – presumably because weaving a convincing lie requires significant effort.
But an effective lie detector – even one that could interrogate the brain directly – relies on the accuracy of the information found there. What if someone genuinely believes something happened when it did not? False memory is a real challenge for courts to deal with. At last year’s Society for Neuroscience meeting in New Orleans, Dan Schacter from Harvard University reported that recalling false memories seem to produce subtly different brainwave patterns to retrieving true ones. The results only showed up by pooling group results, though, so it is too early to think of this as an individual test.
Despite this, there is enough to fuel the fire of those who believe our thoughts should remain private and that no one should be compelled to take a lie-detector test. Others question whether brain scans could ever provide completely reliable evidence. “They fall into same trap as polygraphs,” says Elizabeth Phelps of New York University. “They rely on a guilt response, and sociopaths don’t have normal feelings of guilt.”